Vendor dependencies for 0.3.0 release

vendor/web-time/src/lib.rs

@@ -0,0 +1,144 @@
+//! # Description
+//!
+//! Complete drop-in replacement for [`std::time`] that works in browsers.
+//!
+//! Currently [`Instant::now()`] and [`SystemTime::now()`] will simply panic
+//! when using the `wasm32-unknown-unknown` target. This implementation uses
+//! [`Performance.now()`] for [`Instant`] and [`Date.now()`] for [`SystemTime`]
+//! to offer a drop-in replacement that works in browsers.
+//!
+//! At the same time the library will simply re-export [`std::time`] when not
+//! using the `wasm32-unknown-unknown` target and will not pull in any
+//! dependencies.
+//!
+//! Additionally, if compiled with `target-feature = "atomics"` it will
+//! synchronize the timestamps to account for different context's, like web
+//! workers. See [`Performance.timeOrigin`] for more information.
+//!
+//! Using `-Ctarget-feature=+nontrapping-fptoint` will improve the performance
+//! of [`Instant::now()`] and [`SystemTime::now()`], but the vast majority of
+//! the time is still spent going through JS.
+//!
+//! # Target
+//!
+//! This library specifically targets browsers, that support
+//! [`Performance.now()`], with the `wasm32-unknown-unknown` target. Emscripten
+//! is not supported. WASI doesn't require support as it has it's own native API
+//! to deal with [`std::time`].
+//!
+//! Furthermore it depends on [`wasm-bindgen`], which is required. This library
+//! will continue to depend on it until a viable alternative presents itself, in
+//! which case multiple ecosystems could be supported.
+//!
+//! # Note
+//!
+//! ## Ticking during sleep
+//!
+//! Currently a known bug is affecting browsers on operating system other then
+//! Windows. This bug prevents [`Instant`] from continuing to tick when the
+//! context is asleep. This doesn't necessarily conflict with Rusts requirements
+//! of [`Instant`], but might still be unexpected.
+//!
+//! See [the MDN documentation on this](https://developer.mozilla.org/en-US/docs/Web/API/Performance/now#ticking_during_sleep) for more information.
+//!
+//! ## Context support
+//!
+//! The implementation of [`Instant::now()`] relies on the availability of the
+//! [`Performance` object], a lack thereof will cause a panic. This can happen
+//! if called from a [worklet].
+//!
+//! # Usage
+//!
+//! You can simply import the types you need:
+//! ```rust
+//! use web_time::{Instant, SystemTime};
+//!
+//! let now = Instant::now();
+//! let time = SystemTime::now();
+//! ```
+//!
+//! # Features
+//!
+//! ## `serde`
+//!
+//! Implements [`serde::Deserialize`] and [`serde::Serialize`] for
+//! [`SystemTime`].
+//!
+//! # MSRV
+//!
+//! As this library heavily relies on [`wasm-bindgen`] the MSRV depends on it.
+//! At the point of time this was written the MSRV is 1.60.
+//!
+//! # Alternatives
+//!
+//! [instant](https://crates.io/crates/instant) [![Crates.io](https://img.shields.io/crates/v/instant.svg)](https://crates.io/crates/instant) is a popular alternative! However the API it implements doesn't match [`std::time`] exactly.
+//!
+//! # Contributing
+//!
+//! See the [CONTRIBUTING] file for details.
+//!
+//! # Attribution
+//!
+//! Inspiration was taken from the [instant](https://github.com/sebcrozet/instant/tree/v0.1.12) project.
+//!
+//! Additional insight was taken from the [time](https://github.com/time-rs/time/tree/v0.3.20) project.
+//!
+//! # Changelog
+//!
+//! See the [CHANGELOG] file for details.
+//!
+//! # License
+//!
+//! Licensed under either of
+//!
+//! - Apache License, Version 2.0 ([LICENSE-APACHE] or <http://www.apache.org/licenses/LICENSE-2.0>)
+//! - MIT license ([LICENSE-MIT] or <http://opensource.org/licenses/MIT>)
+//!
+//! at your option.
+//!
+//! ## Copyright
+//!
+//! A majority of the code and documentation was taken from [`std::time`]. For
+//! license information see [#License](https://github.com/rust-lang/rust/tree/1.68.1#license).
+//!
+//! ## Contribution
+//!
+//! Unless you explicitly state otherwise, any contribution intentionally
+//! submitted for inclusion in the work by you, as defined in the Apache-2.0
+//! license, shall be dual licensed as above, without any additional terms or
+//! conditions.
+//!
+//! [CHANGELOG]: https://github.com/daxpedda/web-time/blob/v1.1.0/CHANGELOG.md
+//! [CONTRIBUTING]: https://github.com/daxpedda/web-time/blob/v1.1.0/CONTRIBUTING.md
+//! [LICENSE-MIT]: https://github.com/daxpedda/web-time/blob/v1.1.0/LICENSE-MIT
+//! [LICENSE-APACHE]: https://github.com/daxpedda/web-time/blob/v1.1.0/LICENSE-APACHE
+//! [worklet]: https://developer.mozilla.org/en-US/docs/Web/API/Worklet
+//! [`Date.now()`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/now
+//! [`Instant`]: https://doc.rust-lang.org/std/time/struct.Instant.html
+//! [`Instant::now()`]: https://doc.rust-lang.org/std/time/struct.Instant.html#method.now
+//! [`SystemTime`]: https://doc.rust-lang.org/std/time/struct.SystemTime.html
+//! [`SystemTime::now()`]: https://doc.rust-lang.org/std/time/struct.SystemTime.html#method.now
+//! [`std::time`]: https://doc.rust-lang.org/stable/std/time/
+//! [`performance.now()`]: https://developer.mozilla.org/en-US/docs/Web/API/Performance/now
+//! [`Performance.timeOrigin`]: https://developer.mozilla.org/en-US/docs/Web/API/Performance/timeOrigin
+//! [`Performance` object]: https://developer.mozilla.org/en-US/docs/Web/API/performance_property
+#![cfg_attr(
+	any(not(feature = "serde"), not(target_family = "wasm")),
+	doc = "[`serde::Deserialize`]: https://docs.rs/serde/1/serde/trait.Deserialize.html",
+	doc = "[`serde::Serialize`]: https://docs.rs/serde/1/serde/trait.Serialize.html"
+)]
+//! [`wasm-bindgen`]: https://crates.io/crates/wasm-bindgen
+
+#![cfg_attr(docsrs, feature(doc_cfg))]
+
+#[cfg(all(target_family = "wasm", target_os = "unknown"))]
+mod time;
+#[cfg(any(all(target_family = "wasm", target_os = "unknown"), docsrs))]
+#[cfg_attr(docsrs, doc(cfg(Web)))]
+pub mod web;
+
+#[cfg(not(all(target_family = "wasm", target_os = "unknown")))]
+pub use std::time::*;
+
+#[cfg(all(target_family = "wasm", target_os = "unknown"))]
+pub use self::time::*;

vendor/web-time/src/time/instant.rs

@@ -0,0 +1,242 @@
+//! Re-implementation of [`std::time::Instant`].
+
+use std::ops::{Add, AddAssign, Sub, SubAssign};
+use std::time::Duration;
+
+use super::js::PERFORMANCE;
+
+#[cfg(target_feature = "atomics")]
+thread_local! {
+	static ORIGIN: f64 = PERFORMANCE.with(super::js::Performance::time_origin);
+}
+
+/// See [`std::time::Instant`].
+#[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
+pub struct Instant(Duration);
+
+impl Instant {
+	/// See [`std::time::Instant::now()`].
+	///
+	/// # Panics
+	///
+	/// This call will panic if the [`Performance` object] was not found, e.g.
+	/// calling from a [worklet].
+	///
+	/// [`Performance` object]: https://developer.mozilla.org/en-US/docs/Web/API/performance_property
+	/// [worklet]: https://developer.mozilla.org/en-US/docs/Web/API/Worklet
+	#[must_use]
+	pub fn now() -> Self {
+		let now = PERFORMANCE.with(|performance| {
+			#[cfg(target_feature = "atomics")]
+			return ORIGIN.with(|origin| performance.now() + origin);
+
+			#[cfg(not(target_feature = "atomics"))]
+			performance.now()
+		});
+
+		Self(time_stamp_to_duration(now))
+	}
+
+	/// See [`std::time::Instant::duration_since()`].
+	#[must_use]
+	pub fn duration_since(&self, earlier: Self) -> Duration {
+		self.checked_duration_since(earlier).unwrap_or_default()
+	}
+
+	/// See [`std::time::Instant::checked_duration_since()`].
+	#[must_use]
+	#[allow(clippy::missing_const_for_fn)]
+	pub fn checked_duration_since(&self, earlier: Self) -> Option<Duration> {
+		self.0.checked_sub(earlier.0)
+	}
+
+	/// See [`std::time::Instant::saturating_duration_since()`].
+	#[must_use]
+	pub fn saturating_duration_since(&self, earlier: Self) -> Duration {
+		self.checked_duration_since(earlier).unwrap_or_default()
+	}
+
+	/// See [`std::time::Instant::elapsed()`].
+	#[must_use]
+	pub fn elapsed(&self) -> Duration {
+		Self::now() - *self
+	}
+
+	/// See [`std::time::Instant::checked_add()`].
+	pub fn checked_add(&self, duration: Duration) -> Option<Self> {
+		self.0.checked_add(duration).map(Instant)
+	}
+
+	/// See [`std::time::Instant::checked_sub()`].
+	pub fn checked_sub(&self, duration: Duration) -> Option<Self> {
+		self.0.checked_sub(duration).map(Instant)
+	}
+}
+
+impl Add<Duration> for Instant {
+	type Output = Self;
+
+	/// # Panics
+	///
+	/// This function may panic if the resulting point in time cannot be
+	/// represented by the underlying data structure. See
+	/// [`Instant::checked_add`] for a version without panic.
+	fn add(self, other: Duration) -> Self {
+		self.checked_add(other)
+			.expect("overflow when adding duration to instant")
+	}
+}
+
+impl AddAssign<Duration> for Instant {
+	fn add_assign(&mut self, other: Duration) {
+		*self = *self + other;
+	}
+}
+
+impl Sub<Duration> for Instant {
+	type Output = Self;
+
+	fn sub(self, other: Duration) -> Self {
+		self.checked_sub(other)
+			.expect("overflow when subtracting duration from instant")
+	}
+}
+
+impl Sub<Self> for Instant {
+	type Output = Duration;
+
+	/// Returns the amount of time elapsed from another instant to this one,
+	/// or zero duration if that instant is later than this one.
+	fn sub(self, other: Self) -> Duration {
+		self.duration_since(other)
+	}
+}
+
+impl SubAssign<Duration> for Instant {
+	fn sub_assign(&mut self, other: Duration) {
+		*self = *self - other;
+	}
+}
+
+/// Converts a `DOMHighResTimeStamp` to a [`Duration`].
+///
+/// # Note
+///
+/// Keep in mind that like [`Duration::from_secs_f64()`] this doesn't do perfect
+/// rounding.
+#[allow(
+	clippy::as_conversions,
+	clippy::cast_possible_truncation,
+	clippy::cast_sign_loss
+)]
+fn time_stamp_to_duration(time_stamp: f64) -> Duration {
+	Duration::from_millis(time_stamp.trunc() as u64)
+		+ Duration::from_nanos((time_stamp.fract() * 1.0e6).round() as u64)
+}
+
+#[cfg(test)]
+mod test {
+	use std::time::Duration;
+
+	use rand::distributions::Uniform;
+	use rand::Rng;
+	use wasm_bindgen_test::wasm_bindgen_test;
+
+	wasm_bindgen_test::wasm_bindgen_test_configure!(run_in_browser);
+
+	// According to <https://www.w3.org/TR/2023/WD-hr-time-3-20230719/#introduction>.
+	const MAXIMUM_ACCURATE_SECS: u64 = 285_616 * 365 * 24 * 60 * 60;
+	#[allow(clippy::as_conversions, clippy::cast_precision_loss)]
+	const MAXIMUM_ACCURATE_MILLIS: f64 = MAXIMUM_ACCURATE_SECS as f64 * 1_000.;
+
+	#[derive(Debug)]
+	struct ControlDuration(Duration);
+
+	impl ControlDuration {
+		fn new(time_stamp: f64) -> Self {
+			// See <https://doc.rust-lang.org/1.73.0/src/core/time.rs.html#657-668>.
+			let time_stamp = Duration::from_secs_f64(time_stamp);
+			let secs = time_stamp.as_secs() / 1000;
+			let carry = time_stamp.as_secs() - secs * 1000;
+			#[allow(clippy::as_conversions, clippy::cast_possible_truncation)]
+			let extra_nanos = (carry * 1_000_000_000 / 1000) as u32;
+			// CHANGED: Added rounding.
+			let nanos = time_stamp.subsec_micros()
+				+ u32::from(time_stamp.subsec_nanos() % 1000 > 499)
+				+ extra_nanos;
+			// CHANGED: Removed check that would fail because of the additional time added
+			// by rounding.
+			Self(Duration::new(secs, nanos))
+		}
+	}
+
+	impl PartialEq<Duration> for ControlDuration {
+		fn eq(&self, duration: &Duration) -> bool {
+			// Our control `Duration` has perfect accuracy, unlike
+			// [`super::time_stamp_to_duration()`].
+			if self.0 == *duration {
+				true
+			} else if let Some(diff) = self.0.checked_sub(*duration) {
+				diff == Duration::from_nanos(1)
+			} else {
+				false
+			}
+		}
+	}
+
+	#[wasm_bindgen_test]
+	fn sanity() {
+		#[track_caller]
+		fn assert(time_stamp: f64, result: Duration) {
+			let control = ControlDuration::new(time_stamp);
+			let duration = super::time_stamp_to_duration(time_stamp);
+
+			assert_eq!(control, result, "control and expected result are different");
+			assert_eq!(control, duration);
+		}
+
+		assert(0.000_000, Duration::ZERO);
+		assert(0.000_000_4, Duration::ZERO);
+		assert(0.000_000_5, Duration::from_nanos(1));
+		assert(0.000_001, Duration::from_nanos(1));
+		assert(0.000_001_4, Duration::from_nanos(1));
+		assert(0.000_001_5, Duration::from_nanos(2));
+		assert(0.999_999, Duration::from_nanos(999_999));
+		assert(0.999_999_4, Duration::from_nanos(999_999));
+		assert(0.999_999_5, Duration::from_millis(1));
+		assert(1., Duration::from_millis(1));
+		assert(1.000_000_4, Duration::from_millis(1));
+		assert(1.000_000_5, Duration::from_nanos(1_000_001));
+		assert(1.000_001, Duration::from_nanos(1_000_001));
+		assert(1.000_001_4, Duration::from_nanos(1_000_001));
+		assert(1.000_001_5, Duration::from_nanos(1_000_002));
+		assert(999.999_999, Duration::from_nanos(999_999_999));
+		assert(999.999_999_4, Duration::from_nanos(999_999_999));
+		assert(999.999_999_5, Duration::from_secs(1));
+		assert(1000., Duration::from_secs(1));
+		assert(1_000.000_000_4, Duration::from_secs(1));
+		assert(1_000.000_000_5, Duration::from_nanos(1_000_000_001));
+		assert(1_000.000_001, Duration::from_nanos(1_000_000_001));
+		assert(1_000.000_001_4, Duration::from_nanos(1_000_000_001));
+		assert(1_000.000_001_5, Duration::from_nanos(1_000_000_002));
+		assert(
+			MAXIMUM_ACCURATE_MILLIS,
+			Duration::from_secs(MAXIMUM_ACCURATE_SECS),
+		);
+	}
+
+	#[wasm_bindgen_test]
+	fn fuzzing() {
+		let mut random =
+			rand::thread_rng().sample_iter(Uniform::new_inclusive(0., MAXIMUM_ACCURATE_MILLIS));
+
+		for _ in 0..10_000_000 {
+			let time_stamp = random.next().unwrap();
+
+			let control = ControlDuration::new(time_stamp);
+			let duration = super::time_stamp_to_duration(time_stamp);
+
+			assert_eq!(control, duration);
+		}
+	}
+}

vendor/web-time/src/time/js.rs

@@ -0,0 +1,39 @@
+//! Bindings to the JS API.
+
+use wasm_bindgen::prelude::wasm_bindgen;
+use wasm_bindgen::{JsCast, JsValue};
+
+#[wasm_bindgen]
+extern "C" {
+	/// Type for the [global object](https://developer.mozilla.org/en-US/docs/Glossary/Global_object).
+	type Global;
+
+	/// Returns the [`Performance`](https://developer.mozilla.org/en-US/docs/Web/API/Performance) object.
+	#[wasm_bindgen(method, getter)]
+	fn performance(this: &Global) -> JsValue;
+
+	/// Type for the [`Performance` object](https://developer.mozilla.org/en-US/docs/Web/API/Performance).
+	pub(super) type Performance;
+
+	/// Binding to [`Performance.now()`](https://developer.mozilla.org/en-US/docs/Web/API/Performance/now).
+	#[wasm_bindgen(method)]
+	pub(super) fn now(this: &Performance) -> f64;
+
+	/// Binding to [`Performance.timeOrigin`](https://developer.mozilla.org/en-US/docs/Web/API/Performance/timeOrigin).
+	#[cfg(target_feature = "atomics")]
+	#[wasm_bindgen(method, getter, js_name = timeOrigin)]
+	pub(super) fn time_origin(this: &Performance) -> f64;
+}
+
+thread_local! {
+	pub(super) static PERFORMANCE: Performance = {
+		let global: Global = js_sys::global().unchecked_into();
+		let performance = global.performance();
+
+		if performance.is_undefined() {
+			panic!("`Performance` object not found")
+		} else {
+			performance.unchecked_into()
+		}
+	};
+}

vendor/web-time/src/time/mod.rs

@@ -0,0 +1,15 @@
+//! Re-implementation of [`std::time`].
+
+mod instant;
+mod js;
+#[cfg(feature = "serde")]
+mod serde;
+mod system_time;
+
+pub use std::time::*;
+
+pub use self::instant::Instant;
+pub use self::system_time::{SystemTime, SystemTimeError};
+
+/// See [`std::time::UNIX_EPOCH`].
+pub const UNIX_EPOCH: SystemTime = SystemTime::UNIX_EPOCH;

vendor/web-time/src/time/serde.rs

@@ -0,0 +1,177 @@
+//! Serde serialization and de-serialization for `SystemTime`. It aims to be
+//! compatible with Serde's implementation for [`std::time::SystemTime`].
+//!
+//! This implementation was copied from Serde's
+//! [`Deserialize`](https://github.com/serde-rs/serde/blob/5fa711d75d91173aafc6019e03cf8af6ac9ba7b2/serde/src/de/impls.rs#L2168-L2314),
+//! and
+//! [`Sserialize`](https://github.com/serde-rs/serde/blob/5fa711d75d91173aafc6019e03cf8af6ac9ba7b2/serde/src/ser/impls.rs#L730-L747)
+//! implementation.
+
+#![allow(warnings)]
+
+// CHANGED: Replaced occurrences of `tri!` macro with `?`.
+
+use std::fmt;
+use std::time::Duration;
+
+use serde::de::{Error, MapAccess, SeqAccess, Visitor};
+use serde::{Deserialize, Deserializer, Serialize, Serializer};
+
+use super::SystemTime;
+
+impl<'de> Deserialize<'de> for SystemTime {
+	fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+	where
+		D: Deserializer<'de>,
+	{
+		// Reuse duration
+		enum Field {
+			Secs,
+			Nanos,
+		}
+
+		impl<'de> Deserialize<'de> for Field {
+			fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+			where
+				D: Deserializer<'de>,
+			{
+				struct FieldVisitor;
+
+				impl<'de> Visitor<'de> for FieldVisitor {
+					type Value = Field;
+
+					fn expecting(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
+						formatter.write_str("`secs_since_epoch` or `nanos_since_epoch`")
+					}
+
+					fn visit_str<E>(self, value: &str) -> Result<Self::Value, E>
+					where
+						E: Error,
+					{
+						match value {
+							"secs_since_epoch" => Ok(Field::Secs),
+							"nanos_since_epoch" => Ok(Field::Nanos),
+							_ => Err(Error::unknown_field(value, FIELDS)),
+						}
+					}
+
+					fn visit_bytes<E>(self, value: &[u8]) -> Result<Self::Value, E>
+					where
+						E: Error,
+					{
+						match value {
+							b"secs_since_epoch" => Ok(Field::Secs),
+							b"nanos_since_epoch" => Ok(Field::Nanos),
+							_ => {
+								let value = String::from_utf8_lossy(value);
+								Err(Error::unknown_field(&value, FIELDS))
+							}
+						}
+					}
+				}
+
+				deserializer.deserialize_identifier(FieldVisitor)
+			}
+		}
+
+		fn check_overflow<E>(secs: u64, nanos: u32) -> Result<(), E>
+		where
+			E: Error,
+		{
+			static NANOS_PER_SEC: u32 = 1_000_000_000;
+			match secs.checked_add((nanos / NANOS_PER_SEC) as u64) {
+				Some(_) => Ok(()),
+				None => Err(E::custom("overflow deserializing SystemTime epoch offset")),
+			}
+		}
+
+		struct DurationVisitor;
+
+		impl<'de> Visitor<'de> for DurationVisitor {
+			type Value = Duration;
+
+			fn expecting(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
+				formatter.write_str("struct SystemTime")
+			}
+
+			fn visit_seq<A>(self, mut seq: A) -> Result<Self::Value, A::Error>
+			where
+				A: SeqAccess<'de>,
+			{
+				let secs: u64 = match seq.next_element()? {
+					Some(value) => value,
+					None => {
+						return Err(Error::invalid_length(0, &self));
+					}
+				};
+				let nanos: u32 = match seq.next_element()? {
+					Some(value) => value,
+					None => {
+						return Err(Error::invalid_length(1, &self));
+					}
+				};
+				check_overflow(secs, nanos)?;
+				Ok(Duration::new(secs, nanos))
+			}
+
+			fn visit_map<A>(self, mut map: A) -> Result<Self::Value, A::Error>
+			where
+				A: MapAccess<'de>,
+			{
+				let mut secs: Option<u64> = None;
+				let mut nanos: Option<u32> = None;
+				while let Some(key) = map.next_key()? {
+					match key {
+						Field::Secs => {
+							if secs.is_some() {
+								return Err(<A::Error as Error>::duplicate_field(
+									"secs_since_epoch",
+								));
+							}
+							secs = Some(map.next_value()?);
+						}
+						Field::Nanos => {
+							if nanos.is_some() {
+								return Err(<A::Error as Error>::duplicate_field(
+									"nanos_since_epoch",
+								));
+							}
+							nanos = Some(map.next_value()?);
+						}
+					}
+				}
+				let secs = match secs {
+					Some(secs) => secs,
+					None => return Err(<A::Error as Error>::missing_field("secs_since_epoch")),
+				};
+				let nanos = match nanos {
+					Some(nanos) => nanos,
+					None => return Err(<A::Error as Error>::missing_field("nanos_since_epoch")),
+				};
+				check_overflow(secs, nanos)?;
+				Ok(Duration::new(secs, nanos))
+			}
+		}
+
+		const FIELDS: &[&str] = &["secs_since_epoch", "nanos_since_epoch"];
+		let duration = deserializer.deserialize_struct("SystemTime", FIELDS, DurationVisitor)?;
+		// CHANGED: Insert `Duration` directly.
+		let ret = Ok(Self(duration));
+		ret
+	}
+}
+
+impl Serialize for SystemTime {
+	fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+	where
+		S: Serializer,
+	{
+		use serde::ser::SerializeStruct;
+		// CHANGED: Take `Duration` directly.
+		let duration_since_epoch = self.0;
+		let mut state = serializer.serialize_struct("SystemTime", 2)?;
+		state.serialize_field("secs_since_epoch", &duration_since_epoch.as_secs())?;
+		state.serialize_field("nanos_since_epoch", &duration_since_epoch.subsec_nanos())?;
+		state.end()
+	}
+}

vendor/web-time/src/time/system_time.rs

@@ -0,0 +1,111 @@
+//! Re-implementation of [`std::time::SystemTime`].
+
+use std::error::Error;
+use std::fmt::{self, Display, Formatter};
+use std::ops::{Add, AddAssign, Sub, SubAssign};
+use std::time::Duration;
+
+/// See [`std::time::SystemTime`].
+#[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
+pub struct SystemTime(pub(crate) Duration);
+
+impl SystemTime {
+	/// See [`std::time::SystemTime::UNIX_EPOCH`].
+	pub const UNIX_EPOCH: Self = Self(Duration::ZERO);
+
+	/// See [`std::time::SystemTime::now()`].
+	#[must_use]
+	#[allow(clippy::missing_panics_doc)]
+	pub fn now() -> Self {
+		#[allow(clippy::as_conversions, clippy::cast_possible_truncation)]
+		let ms = js_sys::Date::now() as i64;
+		let ms = ms.try_into().expect("found negative timestamp");
+
+		Self(Duration::from_millis(ms))
+	}
+
+	/// See [`std::time::SystemTime::duration_since()`].
+	#[allow(clippy::missing_errors_doc, clippy::trivially_copy_pass_by_ref)]
+	pub fn duration_since(&self, earlier: Self) -> Result<Duration, SystemTimeError> {
+		if self.0 < earlier.0 {
+			Err(SystemTimeError(earlier.0 - self.0))
+		} else {
+			Ok(self.0 - earlier.0)
+		}
+	}
+
+	/// See [`std::time::SystemTime::elapsed()`].
+	#[allow(clippy::missing_errors_doc, clippy::trivially_copy_pass_by_ref)]
+	pub fn elapsed(&self) -> Result<Duration, SystemTimeError> {
+		Self::now().duration_since(*self)
+	}
+
+	/// See [`std::time::SystemTime::checked_add()`].
+	#[allow(clippy::trivially_copy_pass_by_ref)]
+	pub fn checked_add(&self, duration: Duration) -> Option<Self> {
+		self.0.checked_add(duration).map(SystemTime)
+	}
+
+	/// See [`std::time::SystemTime::checked_sub()`].
+	#[allow(clippy::trivially_copy_pass_by_ref)]
+	pub fn checked_sub(&self, duration: Duration) -> Option<Self> {
+		self.0.checked_sub(duration).map(SystemTime)
+	}
+}
+
+impl Add<Duration> for SystemTime {
+	type Output = Self;
+
+	/// # Panics
+	///
+	/// This function may panic if the resulting point in time cannot be
+	/// represented by the underlying data structure. See
+	/// [`SystemTime::checked_add`] for a version without panic.
+	fn add(self, dur: Duration) -> Self {
+		self.checked_add(dur)
+			.expect("overflow when adding duration to instant")
+	}
+}
+
+impl AddAssign<Duration> for SystemTime {
+	fn add_assign(&mut self, other: Duration) {
+		*self = *self + other;
+	}
+}
+
+impl Sub<Duration> for SystemTime {
+	type Output = Self;
+
+	fn sub(self, dur: Duration) -> Self {
+		self.checked_sub(dur)
+			.expect("overflow when subtracting duration from instant")
+	}
+}
+
+impl SubAssign<Duration> for SystemTime {
+	fn sub_assign(&mut self, other: Duration) {
+		*self = *self - other;
+	}
+}
+
+/// See [`std::time::SystemTimeError`].
+#[derive(Clone, Debug)]
+#[allow(missing_copy_implementations)]
+pub struct SystemTimeError(Duration);
+
+impl SystemTimeError {
+	/// See [`std::time::SystemTimeError::duration()`].
+	#[must_use]
+	#[allow(clippy::missing_const_for_fn)]
+	pub fn duration(&self) -> Duration {
+		self.0
+	}
+}
+
+impl Display for SystemTimeError {
+	fn fmt(&self, formatter: &mut Formatter<'_>) -> fmt::Result {
+		write!(formatter, "second time provided was later than self")
+	}
+}
+
+impl Error for SystemTimeError {}

vendor/web-time/src/web.rs

@@ -0,0 +1,49 @@
+//! Platform-specific extensions to [`web-time`](crate) for the Web platform.
+
+#![allow(clippy::absolute_paths)]
+
+use std::time::SystemTime as StdSystemTime;
+
+use crate::SystemTime;
+
+/// Web-specific extension to [`web_time::SystemTime`](crate::SystemTime).
+pub trait SystemTimeExt {
+	/// Convert [`web_time::SystemTime`](crate::SystemTime) to
+	/// [`std::time::SystemTime`].
+	///
+	/// # Note
+	///
+	/// This might give a misleading impression of compatibility!
+	///
+	/// Considering this functionality will probably be used to interact with
+	/// incompatible APIs of other dependencies, care should be taken that the
+	/// dependency in question doesn't call [`std::time::SystemTime::now()`]
+	/// internally, which would panic.
+	fn to_std(self) -> std::time::SystemTime;
+
+	/// Convert [`std::time::SystemTime`] to
+	/// [`web_time::SystemTime`](crate::SystemTime).
+	///
+	/// # Note
+	///
+	/// This might give a misleading impression of compatibility!
+	///
+	/// Considering this functionality will probably be used to interact with
+	/// incompatible APIs of other dependencies, care should be taken that the
+	/// dependency in question doesn't call [`std::time::SystemTime::now()`]
+	/// internally, which would panic.
+	fn from_std(time: std::time::SystemTime) -> SystemTime;
+}
+
+impl SystemTimeExt for SystemTime {
+	fn to_std(self) -> std::time::SystemTime {
+		StdSystemTime::UNIX_EPOCH + self.0
+	}
+
+	fn from_std(time: std::time::SystemTime) -> SystemTime {
+		Self::UNIX_EPOCH
+			+ time
+				.duration_since(StdSystemTime::UNIX_EPOCH)
+				.expect("found `SystemTime` earlier then unix epoch")
+	}
+}